Actually the weight savings is irrelevant. The advantage is in the simplification of the cable assemblies! Did you know that just about every cable assembly in every car is made by hand‽ Hackaday wrote an article all about it:
https://hackaday.com/2022/07/27/the-surprisingly-manual-proc...
By having just one wire to transmit data and power to components in each zone it will be a significant cost savings. It also makes the various automotive engineer's jobs a lot easier.